An arc flash (or arc blast) is a type of electrical discharge resulting from a low impedance connection to ground or another voltage phase in an electrical system. In particular, the arc flash is produced by an electrical breakdown of the resistance of air which occurs when there is sufficient voltage in an electrical system and a path to ground or lower voltage. An arc flash typically releases a massive amount of energy that vaporizes metal conductors in the electrical system, blasting molten metal and expanding plasma outward from the source, and produces a shock wave due to the rapid heating of the gases in the vicinity. The arc flash and the metal plasma produced by the flash rapidly release tremendous amounts of electromagnetic radiation (e.g., light energy ranging from infrared to ultraviolet wavelengths), and this electromagnetic radiation rapidly heats the surfaces that it contacts. For example, the infrared radiation generated during an arc flash can cause severe burns to the unprotected or underprotected skin of individuals in the vicinity of the arc flash.
In view of the dangers posed by arc flashes, protective clothing systems called arc flash suits have been developed to protect workers at risk of exposure to arc flashes, such as electrical workers and electricians. Such suits are designed to provide varying degrees of protection to the wearer, with the requisite or recommended level of protection being determined by the severity of the arc flash that might be encountered while performing work. In order to provide the desired level(s) of protection, these arc flash suits are typically made from relatively heavy fabrics, the prevailing theory and principle of operation being that heavy fabrics block the electromagnetic radiation and provide insulation from the radiant heating caused by the arc flash. However, suits made from such heavy fabrics often become uncomfortable when worn for prolonged periods of time owing, at least in part, to the low air permeability of the heavy fabrics.
Accordingly, there is a need for lighter weight textile materials that protect from the radiation (e.g., near-infrared radiation) generated by an arc flash and are suitable for use in making garments that are comfortable to wear.